Reference Table for "U" Values

"U" Value is the coefficient of transmission, i.e., the transmission of heat through the materials, which compose the building's "envelope," or outer shell.

"U" Value has an inverse relationship to "R" Value. For example, a building with material with an "R" Value of R-11 converts to an "U" Value of 0.09 ( 1/R or 1/11 = 0.09).

The following is a table of common materials and their corresponding "U" Value.

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Walls

Material

Description

"U" Factor

Flat Metal 0" Fiberglass Insulation 1.20
  1" Fiberglass Insulation 0.22
  2" Fiberglass Insulation 0.12
  3" Fiberglass Insulation 0.09
  4" Fiberglass Insulation 0.07
  6" Fiberglass Insulation 0.05
  8" Fiberglass Insulation 0.041
  12" Fiberglass Insulation 0.027
     
Masonry 8" Brick 0.41
  12" Brick 0.31
  16" Brick 0.25
  8" Conic Block, Solid 0.39
  12" Conic Block, Solid 0.36
  4" Conic Block, Hollow 0.51
  8" Conic Block, Hollow 0.39
  12" Conic Block, Hollow 0.37
     
Poured Concrete 2" Thick 0.99
    (140 lb. / ft3) 4" Thick 0.86
  6" Thick 0.75
  8" Thick 0.67
  10" Thick 0.61
  12" Thick 0..55
     
Poured Concrete 2" Thick 0.62
     (80 lb. / ft.3) 4" Thick 0.42
  6" Thick 0.31
  8" Thick 0.25
  10" Thick 0.21
  12" Thick 0.18

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Doors

Material

Description

"U" Factor

Steel No Fiberglas Insulation 1.20
  Insulated 0.65
     
Wood 1" Thick 0.64

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Roofs

Material

Description

"U" Factor

Flat Metal - Roof 0" Fiberglass Insulation 0.90
  1" Fiberglass Insulation 0.26
  2" Fiberglass Insulation 0.16
  3" Fiberglass Insulation 0.11
  4" Fiberglass Insulation 0.071
  6" Fiberglass Insulation 0.05
  8" Fiberglass Insulation 0.039
  12" Fiberglass Insulation 0.027
     
Wood - Roof 0" Fiberglass Insulation 0.48
  1" Fiberglass Insulation 0.21
  2" Fiberglass Insulation 0.12
  3" Fiberglass Insulation 0.10
  4" Fiberglass Insulation 0.075
  6" Fiberglass Insulation 0.052
  8" Fiberglass Insulation 0.04
  12" Fiberglass Insulation 0.027
     
Concrete Deck - Roof 2" Thick 0.30
  3" Thick 0.23
  4" Thick 0.18
     
Sky Lights Single Wall 1.15
  Double Wall 0.70

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Floors - Exterior Exposure

Material

Description

"U" Factor

Floor - Exterior exposure Insulated 0.55
  Un-Insulated 0.81

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Windows

Material

Description

"U" Factor

Glass Single Pane 1.22
  Double Pane 0.70
     
Fiberglass Panels   1.09

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Cold Mass Specific Gravity

Material

Specific Gravity

Steel 0.12
Aluminum 0.23
Copper 0.09
Cast Iron 0.11
Cement 0.19
Concrete (140# / ft3) 0.16
Sand & Stone 0.19
Glass 0.16
Rubber 0.48
Wood 0.50

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